This applicant has led the world in research and development aimed at realizing biped robots capable of walking activities closely resembling those of human beings. And through the biped robots it proposed up to now has enabled stable robot walking on level ground, upgrades and downgrades, one-leg standing, and ascent/descent of stairs and level differences, thus realizing biped robots capable of adapting to various existing locomotion environments.
Further, it has made feasible use of arms connected to the robot body for operations such as tightening of screws and nuts with a driver (screwdriver) or wrench (spanner), and, in addition, has, by systematically coordinating movements of the legs and arms, made it possible to conduct complex operations such as opening/closing and passing through doors and pushing hand carts. These operations are the result of arm-leg cooperation achieved on a high-order and can be said likely to be a major factor in markedly upgrading compatibility with humans.
Thus the biped robots being researched and developed by the applicant have replaced people in performing various operations in existing operating venues (home, factory etc.) and, for the first time ever, suggested their potential to make coexistence with humans a reality.
In its research and development of these biped robots, however, the applicant has given the robots heights (total length in the vertical direction when in upright posture) of 1600 mm to 1800 mm, near average adult height, not only to make their walking movements close to those of human beings but also to give them a more human-like appearance.
Moreover, various technologies have been put forward regarding biped robots, including diverse proposals with respect to their size. In papers such as “Design and Development of Research Platform for Perception-Action Integration in Humanoid Robot: H6” (5th Robotics Symposia) and “Preliminary Motion Experiments of a Humanoid Robot Saika-3” (18th Annual Conference of the Robotics Society of Japan), for example, biped robots given a height of 1200 mm to 1300 mm are proposed from the aspects of enabling activities in existing operating spaces and achieving small size and light weight.
A number of inconveniences arise when an attempt is made to put a biped robot of the approximately 1600 mm to 1800 mm height adopted by the applicant heretofore into operation in an existing operating space. One that can be mentioned is the amount of battery power consumption. Moreover, greater height is accompanied by increased weight, but the lightest weight possible is preferable when coexistence with people at home, factories and the like is a consideration.
Further, there are many objects subject to operation (working) in an operating space, particularly in a home environment, which are ergonomically located at heights facilitating use not only by adults but also by children, wheelchair users and others, so that it cannot be said that a size near the average adult height (more exactly, the height of the shoulder joints determined therefrom, still more exactly, the arm linkage swing range (height) determined by the shoulder joint height) is necessarily appropriate for the height of the objects subject to operation. Furthermore, in the interest of still better compatibility with people, a robot should preferably be of a size that makes it more likable to people, and from this point also, it cannot be said that a size near average adult height is necessarily appropriate.
On the other hand, points such as weight reduction and likability can be improved by adopting a height of or near 1200 mm to 1300 mm as indicated by the aforesaid prior art. The fact is, however, that the aforesaid prior art etc. has fallen short of giving any consideration to joint height in actually performing operations or to size-related issues such as arm linkage length and the like, and when such a biped robot has actually been set to performing operations, it has been merely scaled down without optimizing the height relationship with the objects, which has made performance efficiency low and led to the following various problems being left unresolved.
For example, in the multi-degree-of-freedom arms of a robot (in a biped robot, the leg linkages and the arm linkages; the shoulder joints of the arm linkages being a particular concern here) there are generally present singularities (singular points) that restrict their movement, and, where consideration is given to performance, these singularities should preferably avoided in determining operation procedures.
Further, in performing different kinds of operations, the position of the object needs to be accurately ascertained with a visual sensor and, therefore, the relative positional relationship between the visual sensor and the object must be thoroughly taken into account.